Bangkok flooding is chronic problem

BANGKOK WILL continue to experience flooding after heavy rains unless water-drainage problems including roads and canals are solved, water-management experts have said.

Heavy rain was to blame for yesterday’s floods in 25 areas around Bangkok after up to 170 millimetres of rain fell on the capital on Wednesday night, the Bangkok Metropolitan Administration (BMA) stated.

Bangkok faced the prospect of more flooding as the Meteorological Department predicted more heavy rains last night and this morning.

The heavy rains turned many streets of the city into canals and seriously worsened rush-hour traffic, causing many commuters to arrive late at work or school. One of the worst flooded areas was the Lat Phrao intersection at Ratchadaphisek Road, where the floodwaters reached about 30 centimetres and seriously disrupted traffic.

BMA drainage and sewerage director Sompong Wiangkaew said the heavy rains were more than the city’s drainage system could cope with.

“We are trying our best to save our city from flooding, but the rain was far too heavy for our drainage system, which can accept around 100 to 120 millimetres. Last night, total rainfall was about 170 millimetres,” Sompong said.

“Moreover, we could not drain the floodwater out of the street properly, because the canals were already full of water from the rains, even though we had decreased the water levels in the canals in advance.”

Sitang Pilailar, a lecturer at the Water Resources Engineering Department at Kasetsart University, said the reasons the BMA cited were chronic problems for the city.

“Bangkok will still flood every time after heavy rain, if the water cannot drain from the roads to the drainage pipes and to the canals properly,” Sitang said.

She said the first problem was that the drainage system mixed with the sewer system, so pipes were already full of wastewater. Moreover, during the floods in 2011, sand was dumped into the drainage system that had not been cleared out completely, lessening the capacity of the city’s drainage pipes by half.

Another problem was lack of preparation before the rain, Sitang said, adding the BMA usually received weather predictions from the Meteorological Department so water levels in the canals could be lowered in advance, but this time the BMA had not performed well.

“In addition to these problems, we still have the issue that many old communities suffer from chronic flooding because their location is lower than street level, so the water from the road drains into their communities instead of into the drainage pipes. The garbage in the drainage system is also significant, as many people still throw litter into drainage pipes and canals,” Sitang said.

“This is a task for all of us to tackle. The BMA has to be better prepared for flooding and maintain the drainage system to make sure that it can work properly, while the people also have to avoid clogging the drainage system with garbage if we want to sustainably solve the flooding problem in Bangkok.”